As the power of tractors and agricultural efficiency has increased, agricultural implements such as planters have increased in span, or width, to accommodate a larger number of individual row units. Planters generally include a main frame having a forward hitch assembly for drawing by a tractor and left and right wing sections pivotally attached to a portion of the main frame. The pivoting wing connections allow the wings to fold relative to the main frame for transport and storage of the planter.
Traditional row crop planters have employed individual seed hoppers affixed to each individual seed-planting row unit. These require filling with seed by hand from bags, or auger or gravity flow from seed unit containers as supplied from a seed company. The process is labor intensive and time consuming, so systems have been devised whereby large centrally located seed hoppers can be bulk-filled with gravity boxes or auger seed tender systems, saving time and reducing labor.
However, the addition of the centrally located seed hoppers has created additional problems. The hoppers have added significant weight (over 5000 lbs.) to center transport axles by moving previously distributed weight to the center of the planter. The additional weight has significantly increased the contact pressure of the main transport tires on the soil, causing compaction, which may result in lower crop yield.
The weight redistribution has also removed approximately 200 lbs. of weight potential from each individual row units. Planter row units require down force to facilitate and maintain soil penetration by their opener blades to open a seed furrow of consistent depth in the soil for planting. With the weight of local seed hoppers now removed, consistency of soil penetration and furrow depth in hard soil, especially in no-till soil is compromised. To help counteract this problem, means of applying spring, pneumatic or hydraulic down force to row units have been employed. The down force has led to yet another problem. The down force has created lift on the tool bar, on which row units are mounted, lowering ground engaging force and tire contact pressure on the ground, which results in slippage of traction-drive tires on the surface of the ground. The change can result in planting skips or inconsistent spacing, which can adversely affect crop yield.
To counter the problems mentioned above, a means to apply down force between the planter center frame and tool bar wings at the contour-following wing flex-points has been employed. The down force has effectively improved both situations, but only for a given load case, as the force applied is constant. As a field may include varying ground hardness and conditions, the amount of down force applied in one area may not be appropriate for other areas. Thus, a field will not be planted consistently, which would affect the overall crop yield for the field.
Therefore, there is a need in the art for a system that can control the amount of down force applied to the central toolbar and wings such that the planting depth will be consistent and soil compaction minimized for varying ground hardness conditions. There is also a need in the art for a system that will automatically update the amount of down force applied at the wings based upon real-time changes of ground hardness in a field.